1. Field of the Invention
The present invention relates to an electron emission element and a process for producing the same. More particularly, it relates to the electron emission element which is used in a display device or a micro-fabrication device such as CRT and the process for producing such a device.
2. Description of the Related Art
Japanese Patent Application Laying Open (KOKAI) No. 64-86427 discloses an electron emission element and a process for producing the element which is applicable to a flat CRT or the like. The electron emission element disclosed in the patent document is constituted in such a way that a recess is formed in an oxide film of SiO.sub.2 so as to form a cathode chip having a tip in the recess and that a gate is formed on the oxide film surface.
The flat CRT has not been commercialized yet. In order for the flat CRT to be accepted in the market, it is necessary to not only upgrade the display quality of the CRT but also lower its cost as well.
The display quality of the CRT depends on the evenness of luminance. Therefore, to upgrade the display quality, it is efficacious to even the electron emission flow from each chip to minimize the luminance distribution on the display by constituting one pixel (picture element) from a plurality of cathode arrays. The density of the cathode array, i.e., the density of electron emission area in the array is about 10.sup.5 /cm.sup.2 to 10.sup.7 /cm.sup.2 .
Also, to lower the cost, it is necessary to simplify the electron emission structure of the element to raise the throughput of production of the elements.
However, in accordance with the electron emission element of the related art so far, the density of the electron emission area or member is low and the throughput is insufficient to commercialize the flat CRT since the chip and the gate of the element are formed with the use of a photomask.